| ObjectivesThe objectives of this study are to compare pulse Doppler blood flow parameters of renal arteries at different levels in Type2Diabetes Mellitus patients with or without hypertension and in normal controls, to evaluate intra-renal hemodynamic changes caused by hypertension, and to explore the possible correlation factors of resistive index of renal arteries at different levels in type2diabetes mellitus.MethodsWe studied212type2diabetes mellitus patients with or without hypertension that underwent renal Doppler Ultrasonography in our hospital from December2010to March2013. The patients were divided into2groups:type2diabetes patients with hypertension (n=122) and type2diabetes patients without hypertension (n=90). A total30normal adults were investigated in this study ts normal control. We collected histories of hypertension, diabetes, tobacco use and medications while body mass indices, waist circumference and blood pressure were measured. Subjects underwent biochemical tests including blood and urine chemistry, hemoglobin Alc, fasting blood glucose, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol, serum creatinine, etc. Urinary albumin-creatinine ratios (ACR) and estimated glomerular filtration rates were calculated. Renal ultrasonography examination was used to measure the kidney length, width, thickness in each patient and control. It was also used to get pulsed Doppler blood flow velocity parameters such as peak systolic velocity and end diastolic velocity of main renal arteries, segmental renal arteries and inter-lobar renal arteries. PI and RI were calculated based on measurements.Results1. The average thickness of kidneys in diabetes patients was higher than that of normal controls (P<0.05).2. Diabetes patients with hypertension have higher average levels of systolic blood pressure, diastolic blood pressure and pulse pressure compared with diabetes patients who do not have hypertension. There were no significant differences between these two groups in age, duration of diabetes, hemoglobin Alc, fasting blood glucose and eGFR. There were more patients with microalbuminuria and macroalbuminuria in diabetes patients with hypertension than without. The average RIs of diabetes patients with hypertension in renal arteries at all levels were significantly increased compared with diabetes patients without hypertension [(0.68±0.06) vs.(0.65±0.05),(0.66±0.05) vs.(0.63±0.04),(0.65±0.05) vs.(0.62±0.04),(P<0.001)]. The average PIs were significantly increased too [(1.21±0.24) vs.(1.19±0.21),(1.20±0.21) vs.(1.09±0.14),(1.16±0.20) vs.(1.06±0.14),(P<0.05)]. Compared with control group, age, BMI, fasting blood glucose, hemoglobin Alc, triglyceride concentration, systolic blood pressure, diastolic blood pressure and pulse pressure were significantly higher while high density lipoprotein cholesterol and estimated glomerular filtration rate were significantly lower in diabetes patients with hypertension. The RIs of diabetes patients with hypertension in renal arteries at all levels were significantly increased compared with control group [(0.68±0.06) vs.(0.65±0.04),(0.66±0.05) vs.(0.62±0.04),(0.65±0.05) vs.(0.62±0.03),(P<0.05)]. The PIs were significantly increased too [(1.21±0.24) vs.(1.15±0.15),(1.20±0.21) vs.(1.07±0.12),(1.16±0.20) vs.(1.08±0.12),(P<0.05)]. Both PIs and RIs of in renal arteries at all levels have no significant differences between diabetes patients without hypertension and normal controls (P>0.05).3. We further observed the differences of RIs and PIs in diabetes patients without proteinuria based on whether they have hypertension. There was no significant difference in age, duration of diabetes, BMI, diastolic blood pressure, hemoglobin Alc, fasting blood glucose and eGFR in the two groups. Systolic blood pressure and pulse pressure were significantly higher in patients with hypertension. The RIs were significantly increased in the group with hypertension at all levels of renal arteries [(0.68±0.06) vs.(0.65±0.04),(0.66±0.05) vs.(0.63±0.04),(0.65±0.05) vs.(0.62±0.04),(P<0.05)]. The PIs in the same group were also significantly increased at segmental renal arteries and inter-lobar renal arteries[(1.21±0.19)vs.(1.09±0.14);(1.17±0.19)vs.(1.07±0.14),(P<0.05)].4. The duration of diabetes, hemoglobin A1c levels, age and pulse pressure are independently associated with RI of main renal artery in all type2DM. Duration of diabetes, hemoglobin A1c level, age, hypertension, eGFR and pulse pressure are independently associated with RI of segmental renal artery. Duration of diabetes, hemoglobin A1c level, age and pulse pressure are associated with RI of interlobar renal artery. The RI was generally higher in patients with higher pulse pressure, older age, longer duration of diabetes and higher hemoglobin A1c level.Conclusion1. Hypertension increases the intrarenal vascular resistance in type2diabetes mellitus, even, even with good blood pressure control (under the target value of130/80mmHg).2. This effect can be detected under pulse Doppler ultrasonography at early stage and RI and PI are useful parameters.3. Renal Doppler ultrasonography has advantages in evaluating intrarenal hemodynamics, renal vascular function and the kidney function in clinical settings. Intrarenal blood flow parameters are sensitive in detecting early diabetic nephropathy. |
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